In the days before movies had soundtracks, it's easy to assume that going to the cinema was a silent experiences. Not so. In fact, movie theaters were packed with innovations to create dramatic soundscapes and keep viewers engaged.

Matt Novak has cast his eye back over the Popular Science archives and stumbled across an article which describes an elaborate system to create all kinds of sound effects right there, in the movie theater itself. Frank Illo had invented a system of sound effect machines unified through a central control system, and was even granted a patent for it. From the Popular Science article, published in September 1919, which describes a wartime "photo-play" (that's a move, by the way):

Let us suppose we are witnessing a photo-play of the war. A locomotive puffs into a station behind the lines, whistle shrieking, bell ringing. Soldiers alight and march away. Their hob-nailed shoes clumping on the cobbles. From the distance comes the deep-toned reverberation of cannon.

All these noises, and more, are produced by a machine invented by Frank Illo, of Dallas, Texas. Briefly the machine is an assembly of many sound-producing instruments unified through a central electrical control; more specifically, a series of shafts, belts, and pulley, diaphragms covered with buckskin, revolving cylinders partly filled with water or with lead shot or steel balls, wooden beams and slats, flexible sheets of tin or other metal, air-valves, whistles, bells, etc., to be used at the will of the operator.

So this machine could make all kinds of sounds, mimicking everything from train engines to canon fire. Sadly, the patent wasn't jumped upon—and the arrival of synchronized sound in the late 1920s killed any demand for live sound effects dead. Poor Frank. [Pacific Standard - Thanks, Justin!]